It works a little differently to that. When someone posts on server B, that post and it's comments get blasted out to all subscribed servers. So server A will already have the post cached if someone is subscribed to that community. The cache in server A will update any time activity happens on server B.
I’m treated well as a software engineer, I’m the envy of my friends of family. But I have friends who are treated like crap in software dev too. So I guess it goes both ways.